Expansible hollow mill.



No. 795,168. PATENTED' JULY 18, 1905.

' H. K. PORTER,

EXPANSIBLB ,HOLLOW MILL.

APPLICATION FILED OCT. 31,1904.

2 SHEETS-SHEET 1,

PATENTED JULY 18, 1905.

- H. K. PORTER.

BXPANSIBLE HOLLOW MILL.

APPLIOATIOH FILED OCT. 31. 1904.

2 SHEETS-SHEET 2.

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-NiTED{ STATES Patented July 18, 1905.

PATE T EXPANSIBLE HOLLOW. MILL.

SPECIFICATION forming part of Letters Patent No. 795,168, dated July 18, 1905.

Application filed October 31, 1904. Serial No. 230,703.

To all whom it malty concern.-

Be it known that I, HENRY K. PORTER, a citizen of the United States, residing at Chelsea, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Expansible Hollow Mills, of which the following is a specification.

My present invention is a modification of and improvement upon the tool described in a pending application of mine filed in the Patent Office July 2, 1904:, and given the Serial No. 215,0at4, and the object of said modification and improvement is to produce a more practically perfect construction of the tool by which like results are obtained with greater convenience in sharpening and adjusting the tool. I. attain said object by the novel construction illustrated in the accompanying drawings, in which- Figure 1 is a side elevation of the tool embodying myinvention. Fig. 2 is a like view, partly in section. Fig. 3 is a front end view of the same. Fig. 4 is a front viewof the band detached. Fig. 5 is a horizontal section, as on line a, Fig. 4:. Fig. 6 is a vertical section, as on line b, Fig. 1. Fig. 7 is a vertical section, as on line 0, Fig. 2. Fig. 8 is a side view of the grooved hollow body with the band removed. Fig. 9 is a side and. end view of a dlsplacing-bar used lnterchangeably with the cutter-bars for a purpose which will be fully explained. Fig. 10 is a side and end view of one of a set of four proportional adjusting plates or shims, a set of "four being provided for each groove. Fig. 11 is a side and end view of one of four gibs which press against the cutting-bars and their ad justing-plates.

Referring to the drawings, in which the various parts are numbered, the same number referring to the same part in the various figures in which it is shown, the number 12 represents the clamp or band which surrounds the grooved body 13, in which the cutting bars or knives 14 15 16 17 are fitted in corresponding grooves 18 19 2O 21. The cutter carrier or body 13 terminates in a round shank 22, by which the tool is usually held and used in a machine, or it may be otherwise constructed and attached by means of a face-plate. The grooved body is bored centrally in line with the axis of-the tool, as at 12;, and thereby made hollow from its front face to near the shank 22. The grooves in which the knives are held may be cut in the body at an angle of about ten to fifteen degrees with a plane passing through the axis of the body to give the cutters when heldtherein the proper front rake, and the cutting edges when properly adjusted longitudinally are radial to the axis of the tool. The body of the tool is formed with a shoulder 22,}, against which the rear side of the band 12 is pressed when in place, as shown in Figs. 1 and 2. The knives are constructed from quadrate bars of steel of suitable dimensions and on their front ends are properly ground to effective cutting edges 23' 24 25 26 when assembled and properly adjusted in their grooves, their interior corners 27 28 29 30 being slightly beveled to. render the cutters self-centering on the end of the stock operated upon.

Any practical number of cutters may be used; but I have found four in practical use on stock of various shapes to be preferable and most efficient. Nearly opposite the inner end of the centralhole 121" in the body 13 a transverse clearing-hole 31 is bored centrally through the axis of the body. Adjacent to the front face of the circular shoulder 22.} there are four notches, as 32 in Fig. 8., cut into the body through the sides of the grooves, as shown at 32 33 35, Fig. 7, and for a purpose which will be explained. Four shims or proportional adjustingqolates, one of which (numbered 36) is shown in Fig. 10, are employed in like sets in each groove, together with the cutting-bar, and a gib 37 (shown in Fig. 11) is also employed in each groove, but always thicker than and projecting slightly above the depth' of the groove. Toprevent any endwisc movement of the plates 36 in their grooves, each plate is formed with an edge projection 36%, that interlocks with one of the side notches 32 33 34 35, according to the groove it occupies, and thus is secured against endwise movement. The gibs are also each formed with an edge projection 38, that fits into and interlocks with said side notches in the grooves with like purpose and eifeet and in the same manner as in the case of the adjusting-plates. The sets of four adjustingshims thus constructed are in this tool all contained in their respective grooves upon one side or the other or partly upon the inner side and partly on the outer side of the cutter-bar, as the required adjustment may determine, and the gib is pressed against the outer face of the cutter-bar or against the outer shim, as the case may be, by the bandscrews. This tool is not adjusted with reference to the size or diameter to which it is to reduce the stock by an endwise movement of the cutter-bars, as such adjustment cannot be effected in that manner to any practical extent. Such adjustment can only slightly vary the relations of the cutting edges to each other a in that longitudinal direction without making the tool inoperative, as they cut on radial lines and cannot be projected beyond that position or withdrawn therefrom without becoming ineffective. The only practical adjustment having reference to any considerable variation of the diameter of the stock out that can be accomplished in this tool is by expansion or bodily movement of the cutters on radial lines, and the only practical means of accomplishing such adjustment in a tool of this character is by the employment of the proportional shims or plates in the bottom of the grooves, varying the positions of the cutters therein by permutation of the measuringrshims and securing them in adjustment by means of opposite clamping devices or screws, as ,39 11 42.

The cutting-blades, which are inclined to the radial planes coincident with their cutting edges and which project to a limited extent beyond the front of the hollow body, are adjustable practically only expansibly, as stated, and not longitudinally on converging lines. For the purpose of such expansible adjustment four metallic shims of various thicknesses, preferably one sixty-fourth one thi rty-second, one-sixteenth, and one-eighth of an inch, are provided for each groove. WVith such sets of fourin each groovecombinations can be formed by permutation that will enable the mechanic to cut therewith many sizes, ranging from one thirty-second to fifteen thirty-seconds by degrees of exact measurement of one thirtysecond of an inch. If the tool is desired for cutting large numbers of screw blanks or analogous pieces of auniform size, the adjusting-shims may be omittedand a non-adjustable tool fitted for the required size. Four spring -buttons 13 4:4 4:5 46 are pivotally screwed to the body ofithe tool and arranged so as to be turned in recesses (Z c in the band and to extend across their respective adjacent grooves to bear upon the parts in the grooves, so as to secure them in place when the pressure of the clamping-screws, and maybe the band, are removed. The gibs, which, as before stated, always project slightly above the groove, serve as elevated bases for the bearings of the ends of the clamping-screws, and thus permit the use of larger bearing ends to the screws and keep them disengaged from the grooves, so that the band can be freely slipped off the body of the tool with but slight relaxation of the pressure by the turning of the clamping-screws.

To facilitate the removal of the cutters for grinding or any purpose from the carrier without disarranging the adjustment of the parts, I employ in combination with the grooves a set of four displacing-bars or interchangeable non-cutting bars 47 of exactly the same size as the cutting-bars. When it becomes necessary to sharpen the cutting edges, they can be readily removed by means of said displacing-bars, like 47, without disarranging the adjustment of the tool as to the relative positions of the cutting edges. The pressure of the clamping-screws being slightly relaxed, the cutters are pushed endwise out of the head by the use of the non-cutting bars, which follow the retreating cutters into the grooves, exactly filling the spaces vacated by them and excluding all dirt therefrom, and the contents of the grooves are all held in the same firm adjustment by turning the clamping-screws to press the parts against the substituted displacing-bars 4.7. In replacing the cutters the pressure is relaxed on the displacing-bars, and they are forced out by the cutters in the same manner that the cutters were forced out by them without disturbance of the relations of other )arts when by tightening the claiin )sci'e\vs the tool is again in cuttingorder precisely as before the removal of the cutters. This provision greatly facilitates the practical use of the tool and keeping the same in adjustment and good working order with but slight loss of time.

Only four bimling-screws 39, 40, 4.1, and 42 are shown, but as many more might be employed in the opposite sides of the band. In such cases it would be preferable to make the additional screws in the form of plugscrews to confine them within the circuit of the band to avoid interference with any other parts of the machine or attachments in which the tool is used. In the construction illustrated the screws 39 and il bear against the body 13, while the screws 40 and 42 bear against the gibs 37, which oppose their ends. Upon the interior sides of the band opposite the inner ends of the binding-screws 39 10 41 12 are four interior projections or bosses 18 4:9 50 51. The height of these bosses is varied to the extent of the projection of the gibs and to correspond to the'difl'erence in the opposite screw on account of .two of their opposing screws bearing upon the gibs 37 and the other two upon the body 13, the lower bosses 18 and 50 opposing the screws 39 and 4:1,.whieh bear upon the body 13, while the higher bosses 4C9 and 51 oppose the screws 40 foo and 42, which bear upon the gibs 37, as shown most clearly in Fig. 3, in which the shims are also shown as partly on the inner side of the groove, with the cutter pressing against them, and partly on the outside of the bar,

where they are simply on deposit awaiting a change of adjustment by transferring them, one or more, to the opposite side of the cutter.

The novel construction herein described constitutes a hollow mill with eXpansible adjustment of the cutters by exactly-measured degrees and one unusually effective and convenient in practical use, the accessory bars, employed to facilitate the displacement of the cutters for sharpening and their replacement without disturbance of their expansible adjustment, saving time and trouble in keeping the tool in good working order, and the face of the annular enlargement of the body or shoulder 22%, through which the grooves are also cut, serves to reinforce the weak sides of the notches in the grooves adjacent thereto and also serves as a stop against which the band 12 is pressed and facilitates the placing of the band upon the body with respect to the proper location of the clampingscrews therein relatively to the gibs and the parts of the body upon which they are arranged to press.

I claim 1. An expansible hollow mill comprising a body provided with a plurality of grooves; a plurality of cutters fitted in the said grooves and having notches in their side walls; a gib fitted in each of the said grooves and each having an edge pro ection by which it Is interlocked with the notched side of its groove,

threaded in the band and. arranged to produce pressure on the gibs to secure the cutters in place, all substantially as described.

2. An expansible hollow mill comprising a body provided with a plurality of grooves having notches in their side walls; a plurality of cutters fitted in the said grooves; sets of adj ustable measuring-shims fitted to said grooves and provided with projections by which they are interlocked with the said notches against endwise movement; gibs also fitted in said grooves and also having projections by which they are similarly interlocked with the said body; and an encircling band provided with means for producing pressure upon the contents of the grooves, to secure the same in place, all substantially as described.

3. An expansible hollow mill comprising a grooved body; cutters fitted in the grooves; interlocking gibs also fitted in the grooves and arranged to secure the cutters therein; and pivoted buttons attached to the body between the grooves and arranged to be turned across the grooves over the contents thereof to hold the latter in place,temporarily, when the band is removed, substantially as specified.

4. An expansible hollow mill comprising a body having an annular shoulder around the same, and grooves in the body and. through the shoulder; notches cut in the side of the grooves adjacent to the shoulder; cutters fitted in the grooves; gibs fitted in the grooves and adapted to interlock with the said notches; measuring shims fitted to the grooves and having projections adapted to interlock with the said notches; a band encircling said body and abutting against said shoulder; and means, cooperating with said band, for securing the cutters, shims and gibs in place in the said grooves, all substantially as specified.

Signed at Boston, Massachusetts, October HENRY K. PORTER. Witnesses:

EUGENE HUMIHREY, E. J. PARMENTER. 

